java - ExecutorService 停止并等待另一个 ExecutorService 在 Java 中完成

Question

我有两个 ExecutorService 实例:一个有 4 个线程，另一个有 20 个线程。我希望单击按钮后，服务 1 就会停止并等待服务 2 结束。之后，服务1继续运行。

我尝试使用 wait 和 notify 来执行此操作，但它没有按预期工作:

执行服务1:

    public void readFile(JTextArea textArea) {
    try {
        File file = new File(this.fm.fullPath);
        if (!file.exists()) {
            return;
        }
        BufferedReader br = new BufferedReader(new FileReader(this.fm.fullPath));

        ExecutorService executor = Executors.newFixedThreadPool(main.TOTALSTRINGS);

        String line = br.readLine();

        int i=1;
        while (line != null) {
            powThread t = new powThread("Thread" + (i+1), line, textArea);
            executor.execute(t);
            line = br.readLine();
            i++;
        }

        executor.shutdown();
        Thread t = new Thread() {
            public void run() {
                try {
                    executor.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
                    br.close();
                } catch (Exception e) {

                }
            }
        };
        t.start();

    } catch (IOException e) {
        e.printStackTrace();
    }
}

ExecutorService2:

    public void generateNumStrings(JTextArea textArea) {
    StringGenerator sg = new StringGenerator();

    int[] dynamicThreads = main.calcThreadsTotal();
    int totalThreads = dynamicThreads.length;

    ExecutorService executor = Executors.newFixedThreadPool(totalThreads);

    for(int i=0; i<totalThreads; i++) {
        generateThread t = new generateThread("Thread" + (i+1), sg, dynamicThreads[i], this.fm);
        executor.execute(t);
    }

    executor.shutdown();

    Thread t = new Thread() {
        public void run() {
            try {
                textArea.setText("");
                executor.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
                textArea.append("File write successfully!");
            } catch (InterruptedException e) {

            }
        }
    };
    t.start();
}

Answer 1

您可以使用AtomicReference在第一个 ExecutorService 中包装第二个 ExecutorService；如果第二个 ExecutorService 尚未实例化，则返回 null，然后 awaitTermination 如果引用非空。我假设 readFile 和 generateNumStrings 位于同一个类中，如果不是，那么您需要找到某种方法来制作 AtomicReference generateNumStrings

可见

private final AtomicReference<ExecutorService> ref = new AtomicReference<>(null);

private void awaitTermination() throws InterruptedException {
    ExecutorService executor = ref.get();
    if(executor != null) {
        executor.awaitTermination(1, TimeUnit.DAYS);
    }
}

public void readFile(JTextArea textArea) {
...
    while (line != null) {
        awaitTermination();
        powThread t = new powThread("Thread" + (i+1), line, textArea);
        executor.execute(t);
        line = br.readLine();
        i++;
    }
...
}

public void generateNumStrings(JTextArea textArea) {
...
    ExecutorService executor = Executors.newFixedThreadPool(totalThreads);
    ref.set(executor);
...
}